fiddle: release GVL for ffi_call

Some external functions I wish to call may take a long time
and unnecessarily block other threads.  This may lead to performance
regressions for fast functions as releasing/acquiring the GVL is not
cheap, but can improve performance for long-running functions
in multi-threaded applications.

This also means we must reacquire the GVL when calling Ruby-defined
callbacks for Fiddle::Closure, meaning we must detect whether the
current thread has the GVL by exporting ruby_thread_has_gvl_p
in internal.h

* ext/fiddle/function.c (struct nogvl_ffi_call_args):
  new struct for GVL release
  (nogvl_ffi_call): new function
  (function_call): adjust for GVL release
  [ruby-core:71642] [Feature #11607]
* ext/fiddle/closure.c (struct callback_args):
  new struct for GVL acquire
  (with_gvl_callback): adjusted original callback function
  (callback): wrapper for conditional GVL acquire
* ext/fiddle/depend: add dependencies
* ext/fiddle/extconf.rb: include top_srcdir for internal.h
* internal.h (ruby_thread_has_gvl_p): expose for fiddle
* vm_core.h (ruby_thread_has_gvl_p): moved to internal.h
* test/fiddle/test_function.rb (test_nogvl_poll): new test

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52723 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 0 deletions

diff --git a/internal.h b/internal.h
index 7e6f26db11..138f718cd1 100644
--- a/internal.h
+++ b/internal.h
@@ -1320,6 +1320,9 @@ VALUE rb_gcd_gmp(VALUE x, VALUE y);
 VALUE rb_setup_fake_str(struct RString *fake_str, const char *name, long len, rb_encoding *enc);
 #endif
 
+/* thread.c (export) */
+int ruby_thread_has_gvl_p(void); /* for ext/fiddle/closure.c */
+
 /* util.c (export) */
 extern const signed char ruby_digit36_to_number_table[];
 extern const char ruby_hexdigits[];